Khin Khin Tha¹, Ulrich Katscher², Hiroyuki Hamaguchi³, Xinnan Li³, Tomohiro Kawasaki⁴, Shigeru Yamaguchi⁵, Ichiro Yabe⁵, and Hideki Hyodoh^5
1Global Center for Biomedical Science and Engineering, Hokkaido University Faculty of Medicine, Sapporo, Japan, ²Philips Research, Hamburg, Germany, ³Hokkaido University Graduate School of Biomedical Science and Engineering, Sapporo, Japan, ⁴Hokkaido University Hospital, Sapporo, Japan, ⁵Hokkaido University Faculty of Medicine, Sapporo, Japan

This study was aimed to evaluate if electrical conductivity (σ) by electric properties tomography (EPT) could detect variations in the cerebrospinal fluid (CSF) biochemical composition and if optimization of scan and analysis parameters improved the accuracy of in vivo σ measurements. σ values varied among patients and CSF samples with varying CSF biochemical composition, and showed significant correlation with CSF albumin concentration and total cell count. σ may be sensitive to CSF abnormalities. Optimization of scan and analysis parameters is important for the accuracy of in vivo σ measurements. 

Shigeki Yamada^1,2, Yoshiyuki Watanabe³, Tomohito Otani⁴, Shinnosuke Hiratsuka³, Masahiro Yoshimura³, Naoki Takeishi⁴, Shigeo Wada⁴, Marie Oshima², and Kazuhiko Nozaki^1
1Neurosurgery, Shiga University of Medical Science, Otsu, Japan, ²Interfaculty Initiative in Information Studies, Institute of Industrial Science, The University of Tokyo, Tokyo, Japan, ³Radiology, Shiga University of Medical Science, Otsu, Japan, ⁴Mechanical Science and Bioengineering, Graduate School of Engineering Science, Osaka University, Osaka, Japan

The f value calculated by the Intra-Voxel Incoherent Motion (IVIM)  MRI was was high in the areas where the CSF flow was reported to be fast, specifically in the cerebral aqueduct and subarachnoid spaces around the major intracranial arteries. Therefore, f value was considered to reflect flow velocity of CSF, regardless of its direction.  The mean f values in the whole lateral ventricles, anterior part of the third ventricle, ambient cisterns, central sulci, and marginal sulci were significantly lower and that in the foramina of Luschka was significantly higher among 28 iNPH patients, compared with 57 healthy volunteers.

Yoshitaka Bito^1,2, Hisaaki Ochi^1,2, Kuniaki Harada², Ryuji Shirase¹, and Kohsuke Kudo^2
1FUJIFILM Healthcare Corporation, Tokyo, Japan, ²Hokkaido University Graduate School of Medicine, Sapporo, Japan

Low b-value DTI (Low-b DTI) has been recently proposed for investigating the CSF pseudorandom flow. High repeatability of Low-b DTI is essential for the investigation; however, an efficient index evaluating repeatability of both shape and orientation of DT has not been presented. In this study, a new index, angular tensor-correlation-coefficient (ATCC), was proposed and was demonstrated to have good features in understanding the degree of repeatability by Monte Carlo simulation. ATCC was used to evaluate the repeatability of an experiment about Low-b DTI of CSF and showed high repeatability of this experiment.

Jichang Zhang¹, Xinpei Wang¹, Faisal Najeeb², Pengfei Xu¹, Hammad Omer², Penny Gowland³, Sue Francis³, Paul Glover³, Richard Bowtell³, and Chengbo Wang^1
1SPMIC, The University of Nottingham Ningbo China, Ningbo, China, ²COMSATS University Islamabad, Islamabad, Pakistan, ³SPMIC, The University of Nottingham, Nottingham, United Kingdom

This work presents a robust motion corrected free breathing Dynamic Contrast Enhanced MRI (DCE-MRI) reconstruction method called Low rank plus sparse (L+S) with soft weighting which compressed motion blurring by employing a soft weighting matrix. The motion correction performance was quantified in this work. A computer simulation framework based on a modified shepp-logan model was developed with the ground truth to quantify the reconstruction errors.  The proposed method achieved better motion correction and high reconstruction efficiency simultaneously.

Christopher Man^1,2, Zheyuan Yi^1,2, Vick Lau^1,2, Jiahao Hu^1,2, Yujiao Zhao^1,2, Linfang Xiao^1,2, Alex T.L. Leong^1,2, and Ed X. Wu^1,2
1Laboratory of Biomedical Imaging and Signal Processing, The University of Hong Kong, Hong Kong SAR, China, ²Department of Electrical and Electronic Engineering, The University of Hong Kong, Hong Kong SAR, China

Conventional parallel imaging methods mostly utilize the spatial encoding by array of receiver coils to unfold the periodic aliasing artifact resulted from uniformly undersampled k-space data. In scenarios such as low- or ultra-low-field MRI where effective receiver arrays do not exist and SNRs are low, these methods are not generally applicable. This study presents a U-Net based deep learning approach to single-channel MRI acceleration that unfolds the aliasing by exploiting its periodicity. The results demonstrate the aliasing unfolding capability of this method for single-channel MRI even at very high acceleration and in presence of pathologies.

Yajie Wang¹, Haikun Qi², Yishi Wang³, and Huijun Chen^1
1Center for Biomedical Imaging Research, Department of Biomedical Engineering, School of Medicine, Tsinghua University, Beijing, China, ²School of Biomedical Engineering, ShanghaiTech University, Shanghai, China, ³Philips Healthcare, Beijing, China

T1 mapping of the liver has been used for the diagnosis and grading of the liver disease, and the evaluation of the liver function, while conventional liver T1 mapping techniques need breath-holding, have limited slice coverage or need multiple acquisitions. In addition, the accuracy of the T1 quantification is affected by the presence of fat in the liver. In this study, free-breathing water-fat separation and T1 mapping quantification of the whole liver was achieved within one scan using the proposed mGOAL-SNAP sequence. The quantitative accuracy and the in-vivo feasibility of mGOAL-SNAP have been demonstrated in phantom and volunteers studies.

Guoxiang Liu^1,2, Adnan Shah^1,2, Takashi Ueguchi^1,2, and Seiji Ogawa^1,3
1NICT, Osaka, Japan, ²Graduate School of Frontier Biosciences, Osaka University, Osaka, Japan, ³Tohoku Fukushi University, Sendai, Japan

We compare the detectability of multi shot EPI (msEPI) and single shot EPI with GRAPPA (ssEPI-GRAPPA) using D-value maps to show the benefit of BISEPI (Block-Interleaved Segmented EPI) [1] for the same total acquisition time. D-values were derived based on the relationship between target effect, the significance level of detection, the number of time points (volumes), and tSNR [2]. The proposed D-value maps can be a useful quality assurance measure for determining the tSNR gain and activity detection performance of msEPI in comparison to ssEPI-GRAPPA in high-resolution fMRI at 7T.

Masami Yoneyama¹, Takashige Yoshida², Johannes M Peeters³, Jihun Kwon¹, Yasutomo Katsumata³, Shuo Zhang⁴, and Marc Van Cauteren^3
1Philips Japan, Tokyo, Japan, ²Tokyo Metropolitan Police Hospital, Tokyo, Japan, ³Philips Healthcare, Best, Netherlands, ⁴Philips GmbH Market DACH, Hamburg, Germany

Diffusion weighted whole body imaging with background body signal suppression (DWIBS) is an important tool for whole body imaging to e.g. visualize malignant tumor and abnormal lymph nodes. Next to the low intrinsic SNR of DWIBS, direct coronal DWIBS can suffer from another SNR penalty due to the high acceleration factors to minimize distortion. In this work, we compare SENSE, C-SENSE and C-SENSE-AI (CS-AI) accelerated direct coronal DWIBS scans. Results indicate that CS-AI clearly reduces the noise artifacts, boosts the overall image SNR, and improves lesion conspicuity.